Double-hung, tilt-out type windows have become increasingly popular. Much of this popularity is due to the tilt-out feature, which allows both the inside and outside surfaces of the glazing to be cleaned from the inside and facilitates removal and replacement of a damaged sash.
Various tilt-out windows have been equipped with slide blocks, such as the one disclosed in U.S. Pat. No. 4,610,108 to Marshik, the disclosure of which is hereby incorporated by reference herein in its entirety. Marshik discloses a double-hung window having a frame with a set of parallel jamb channels on opposite sides of the frame. Within each jamb channel is a slideably mounted block. A spring balance mechanism is attached to a headplate on each block. A connecting pin extends from opposite sides of a sash into an opening in a locking cam member housed within the block. The pivots allow the sash, which holds the glazing, to be rotated or tilted toward the inside of a room. As the pivots rotate, the cam forces serrated ends of a spring into opposite sides of the jamb channel to lock the block to the frame, thereby preventing the spring balance from moving the block and the sash.
The connecting pin can become disconnected from the block when the sash is tilted toward the inside of a room, if the operator inadvertently lifts while tilting the sash. This can cause the sash to disengage from the frame, requiring realignment prior to tilting the sash back into place. Conventional retention features can be difficult to operate and costly to manufacture. See, for example, the Locking Slide Block of U.S. Pat. No. 5,243,783 to Schmidt, the disclosure of which is hereby incorporated by reference herein in its entirety.